A complex arrangement of metal parts that is capable of discharging a lead peice at very high speeds, high enough to penetrate fleash and thin slabs of wood. Serves as humankind's (so far) permanent replacement for spears, staffs, swords, daggars, etc. as most effective weapons. Most commonly used for self-defense, murder, killing hostiles, recreational shooting, the standard issue weapons for armies, militias, etc.

Guns aren't the problem. It's criminals, irresponsible people, and totalitarian shitheads getting a hold of them that's the problem.

A weapon that has existed since the 13th Century and has been developing more and more, as well as diversifying ever since.
They come in small, handheld forms known as pistols or handguns; or automatic, repeating-fire, styles known as machine guns; and longer types with stocks and that are designed to be fired from the shoulder: these are known as rifles. The many kinds of guns, the mechanical/technical information of a gun, and so on are WAY too long to list here. For additional information I recommend looking at the other examples below.